Meeting Abstract

66.1  Wednesday, Jan. 6  Blastoderm patterning and gap gene interaction in the milkweed bug Oncopeltus fasciatus BEN-DAVID, J; CHIPMAN, A.D.*; The Hebrew University of Jerusalem; The Hebrew University of Jerusalem ariel.chipman@huji.ac.il

The early embryo of the milkweed bug, Oncopeltus fasciatus, appears as a single cell layer – the embryonic blastoderm – covering the entire egg. It is at this blastoderm stage that morphological domains are first determined, long before the appearance of overt segmentation. Central to the process of patterning the blastoderm into distinct domains are a group of transcription factors known as gap genes. In Drosophila melanogaster these genes form a network of interactions, and maintain sharp expression boundaries through strong mutual repression. Their restricted expression domains define specific areas along the entire body. We have studied the expression domains of the four trunk gap genes in O. fasciatus and have determined their interaction through dsRNA gene knockdown experiments, followed by expression analyses. While the blastoderm in O. fasciatus includes only the first six segments of the embryo, the expression domain of the gap genes within these segments are broadly similar to those in Drosophila where the blastoderm includes all 15 segments. Surprisingly, mutual repression between the genes seems to play a much less significant role than it does in Drosophila.